Delivery unit

ABSTRACT

In previous feed units with a fuel pump arranged in them, the inlet of the fuel pump is preceded by a filter. Filters of this type consist, as a rule, of a tubular filter fabric, into which a supporting body maintaining the shape is inserted. These filters lie only in a part region of the baffle due to their shaping, with the result that the supply of fuel to the fuel pump is impaired, particularly in the case of a low fuel level.  
     The new feed unit, in particular the bottom region, forms part of the filter housing. The filter fabric is fastened to the baffle in this region and the fuel pump is connected to the filter.

[0001] The invention relates to a feed unit for a fuel tank, in particular for a motor vehicle, with a baffle, with a fuel pump and with a filter preceding the fuel pump.

[0002] Feed units which are to be used in fuel tanks and by means of which fuel is fed from the tank to the internal combustion engine of the motor vehicle are generally known and are therefore state of the art. The fuel pump arranged in the baffle sucks in the fuel from the baffle via the filter. Impurities in the fuel are to be prevented by means of the filter from passing into the fuel pump and from there to the internal combustion engine.

[0003] DE 36 09 906 A1 discloses a filter of this type. It consists of a tubular filter fabric which is connected to a connection piece and via which the filter is fastened to the inlet port of the fuel pump. The filter is led as far as the bottom of the tank, so that, even when the liquid level is low, fuel can be sucked in by the fuel pump over part of the filter fabric. In order to avoid the filter being contracted as a result of the suction effect of the fuel pump, thereby impairing the filter action, a supporting body is inserted into the filter fabric and prevents the filter from being contracted.

[0004] The complicated manufacture of the filter is a particular disadvantage. Thus, the insertion of the supporting body, the shaping of the filter fabric into its final shape and the welding of the edges of the filter fabric necessitate a multiplicity of work steps. In addition, there is the orientation of the filter during the mounting of the latter in the tank.

[0005] The problem on which the invention is based, is to provide a filter for a fuel pump of the type initially mentioned which has a better filter capacity, is simple to produce and can be mounted easily.

[0006] This problem is solved, according to the invention, in that the filter is integrated into the baffle of the feed unit. Part of the baffle is in this case an integral part of the filter in that it is covered by the filter fabric. This part of the baffle thus forms the filter housing. The decisive advantage is that the useful filter surface is enlarged, thus entailing an improved filter capacity. In addition, in this case, the fuel also passes into the filter as a result of gravity, no longer solely due to the suction capacity of the fuel pump. A tubular closed configuration of the filter fabric being avoided, the production of the filter fabric is appreciably simpler and therefore cost-effective.

[0007] In an advantageous refinement, the filter fabric covers a part region of the bottom of the baffle. A particularly reliable fuel supply is ensured when this part region is the lowest region of the baffle. The part region may at the same time have a step-shaped or outwardly curved design. In the case of a baffle without an orifice in the bottom, the entire bottom is advantageously covered by the filter fabric. A particularly large filter surface is thereby obtained.

[0008] In order to prevent the filter from being contracted, it is advantageous to arrange supporting elements between the baffle and the filter fabric. A favorable configuration is obtained when these supporting elements, ribs, are connected to the baffle. The supporting elements may both be snapped in and be integrally molded. In another configuration, the supporting elements are arranged on the filter fabric and support the latter against the baffle.

[0009] The fastening of the filter fabric in the baffle becomes particularly simple when the filter fabric is surrounded by a frame. Latching elements arranged on the frame make particularly simple mounting possible when they are snapped together with latching points in the baffle. An even simpler refinement, with the filter fabric being sealed off effectively relative to the baffle, is obtained when the frame is snapped into a peripheral groove arranged in the baffle.

[0010] In another refinement, the frame is made of plastic and is inserted in a receptacle of the baffle. As a result of the swelling of the plastic, the frame is pressed together with the receptacle, so that the sealing effect occurs.

[0011] It is also advantageous to insert the filter fabric into the baffle and fasten it to the baffle by means of a holding ring. In a further refinement, the filter fabric is welded to the baffle. Support, at the same time with the filter fabric being fixed. is achieved in that the supporting elements have latching points, into which latching elements arranged on the filter fabric engage.

[0012] The invention permits numerous embodiments and, to make its basic principle even clearer, is illustrated in the drawings in which:

[0013]FIG. 1 shows a top view of a baffle,

[0014]FIG. 2 shows a filter fabric,

[0015]FIG. 3 shows the filter fabric in the mounted state,

[0016]FIG. 4 shows a side view of the filter according to the invention,

[0017]FIGS. 5, 6 show fastenings of the filter fabric to the baffle.

[0018]FIG. 1 shows a battle 1 produced by the injection molding method. The part region 2 forms the lowest region of the bottom. Vertical ribs 3 are integrally molded in this part region 2 as supporting elements which extend to a height corresponding to the level of the part region 4. Elements 5 likewise integrally formed in the baffle 1 serve for receiving and supporting the filter. By the elements 5 being arranged in an interrupted manner, the fuel can flow, unimpeded, into the region of the intake pipe. Fuel passes out of the fuel tank, not illustrated, into the baffle 1 via orifices 6 in the bottom of said baffle 1.

[0019] The filter fabric 7 according to FIG. 2 has a shape matched to the part region 2 from FIG. 1. Plastic is injection-molded around the filter fabric 7 on the circumference of the latter, so that a frame 8 is formed. A connection piece 9 integrally molded in one piece with the frame serves for connecting the filter to the fuel pump.

[0020]FIG. 3 shows the filter in the mounted state. The fuel is fed to the internal combustion engine by means of a fuel pump 10. To seal off the filter, the frame 8 is welded to the edge of the part region 4 surrounding the part region 2.

[0021] The filter in FIG. 4 is inserted with its frame 8 into the part region 4 in such a way that the filter fabric 7 covers the part region 2. Swelling caused by the absorption of liquid by the plastic ensures a leaktight fit. The connection piece 9 is supported on the elements 5, while the supporting elements 3 prevent the filter fabric 7 from sinking.

[0022] The fastening of the filter is illustrated in FIGS. 5 and 6. in this regard, the frame 8 according to FIG. 5 has a peripheral latching element 11, for example a hook or bead, which is pushed or snapped in a latching point 12, for example a groove, likewise peripheral along the edge of the part region 4. FIG. 6 shows another type of fastening. The filter fabric 7 or the frame 8 is laid onto a peripheral bearing surface 13. The holding ring 14 is subsequently mounted, which fixes the filter fabric 7 or the frame 8 in its position and has the effect of sealing off. The fastening of the holding ring 14 may take place likewise over its entire circumference in a similar way to FIG. 5 or by means of individual fastening elements. Latching elements 15 additionally integrally molded on the filter fabric 7, in interaction with latching elements 16 fix and support the filter fabric in relation to the part region 2. 

Patent claims
 1. A feed unit for fuel, with a fuel pump and with a filter having a filter fabric, the fuel pump possessing at least one inlet and at least one outlet, and the filter arranged in the baffle being connected to the inlet of the fuel pump, characterized in that a part region (2) of the baffle (1) is an integral part of the filter and this part region (2) is covered by the filter fabric (7)
 2. The feed unit as claimed in claim 1, characterized in that the entire bottom region (1) or a part region (2) of the bottom of the baffle (1) is an integral part of the filter.
 3. The feed unit as claimed in claims 1 and 2, characterized in that supporting elements (3, 16) for the filter fabric (7) are arranged in that part region (2) of the baffle (1) which is covered by the filter fabric (7).
 4. The feed unit as claimed in at least one of the preceding claims, characterized in that the filter fabric (7) is surrounded by a frame (B).
 5. The feed unit as claimed in claim 4, characterized in that the frame (8) is welded to the baffle (1).
 6. The feed unit as claimed in claim 4, characterized in that the frame (8) and that part region (2) of the baffle (1) which is covered by the filter fabric (7) have latching elements (11, 15), by means of which the filter fabric (7) is snapped in the baffle (1).
 7. The feed unit as claimed in claim 4, characterized in that the frame (8) is inserted into the baffle (1) and is fastened in the baffle (1) by means of one or more fastening elements (14). 